Found my huckleberry......

[Pocket]

Originally Posted by cleatus12r

Here's a couple questions for Bill if he ever has time to respond :

Why do the shift functions not correlate to actual speeds. If the revs/mile and gear ratio are correct, then why do the speeds give a representation, but not an actual result?

Why does the anticipated shifting (even if the max. and min. speeds are altered) not seem to do anything regardless if the switch is on or off? This kind of goes along with me trying to get ACTUAL shift speeds out of the shift functions.

I came to the anticipated shifting switch and remembered you posted something about this. So it doesn't work to turn it off.... what about also turning off the switch for "Enable Adaptive Shift Strategy"? Has anyone tried that one yet? There's also switches for "Adaptive X-Y Shift Strategy Enable" (where X-Y is the gear shift for 1-2, 2-3, and 3-4). I didn't know if that would make a difference and give you the shift functions that correlate more with actual speeds. Thoughts?

I'm always a chicken to try new stuff myself, since I'm still so new at tuning.

[cleatus12r]

Actually, going a bit against what was originally thought, the SuperDuty PCMs are able to adapt for actual shift times (how long it takes the shift to actually occur when commanded). If you look a bit deeper into the parameters, you'll see that the shift pressure adaptive limits are +/- 20 PSI. By turning those off (which I always do), whatever shift characteristics you program into shift times/pressures will remain forever.....and the PCM will not alter the shift pressures by itself. That's what I LOVE about the OBS PCMs......they do exactly what you tell them to do every time.

The anticipated shifting switch that I was talking about in the quoted post SHOULD cause the PCM to command a shift at a consistent speed every time, but it still varies. I don't know if it's something that can be taken out or not.

Heck, you never learn anything if you don't try!!! I just alter all sorts of stuff and see what happens. Obviously I stay away from anything that isn't defined or sounds dangerous.

[Pocket]

Ahhh, so Adaptive Shift Strategy deals with shift pressures rather than shift times. I saw the shift pressure parameters in there, but I also saw some other related stuff and had absolutely no idea what it was.

I may try to turn off the anticipated shifting switch to see how it works on VDH2 tuning, and if I get a different result than what you got.